SEO Improvements (#983)

* [site,seo][xs]: add custom _document with lang prop, add description to meta tags, make title larger

* [site,seo][xs]: add apple touch icon, add alt props to images

* [site,seo][xs]: add icon to default seo

* [site,seo][s]: implement next-sitemap

* [site,seo][s]: review page titles

* Rebuild package-lock.json files

* Regenerate package-lock

site/layouts/docs.tsx

@@ -13,7 +13,7 @@ export const DocsLayout: React.FC<any> = ({ children, ...frontMatter }) => {
               <time dateTime={created}>{formatDate(created)}</time>
             </p>
           )}
-          {title && <h1>{title}</h1>}
+          {!frontMatter.disableTitle && title && <h1>{title}</h1>}
         </div>
       </header>
       <section>{children}</section>